Generally, operators and drivers (referred to hereinafter only as drivers) for an airplane, ship, vehicle, two-wheeled vehicle, heavy equipment, etc. (referred to hereinafter only as transportation devices) must often inevitably drive the transportation devices even under the condition that they are tired or overworked, because their driving schedules are not fixed. For this reason, the drivers may encounter the danger of serious accidents due to sleepy driving resulting from their fatigue.
On the other hand, the above drivers for the transportation devices usually make self-diagnoses of their bodies on the basis of symptoms and habits appearing on their bodies to determine whether they are currently overworked or tired. When the drivers determine that they are tired, they drive the transportation devices after sleeping or taking a reset. However, such self-diagnoses of the drivers are unscientific and, when certain symptoms instantaneously appear while driving, the drivers must judge the current conditions by themselves. As a result, it is the reality that the drivers for the transportation devices are always exposed to the danger of serious accidents.